While looking for more info on the plate that I have (which I've decided _must_ be facsimile based), I came across Mitch Baker Marketing (bakersports2007) on eBay. He's selling the same plate as mine and claims it to be 100% authentically signed. I don't see how Mantle would make the same mistake in signing the "y" as  "v" in his first name three times without some level of degradation of the ink elsewhere in the signature. That's why I concluded mine to be a facsimile.

Anyway, looking at his listing, he states that "we are a UACC certified dealer" (sic), but UACC doesn't have his name or his company's name on the dealer page. I tried looking up the website for his company, and it's apparently someone who has a marketing agreement with Lawrence Tynes. (He's the only person on the "clients" page.) Also, the site mentions distribution through Michael's Sporting Goods, so I figured that might be another possible starting point.

If anyone has dealt with them (either positive or negative experience), please advise. Thanks everyone!